1. Field of the Invention
The invention relates to a bi-directional cooling arrangement for use with an electronic component enclosure, such as a processor book, for example, and in particular, to a cooling system used within a processor book, which delivers a cooling gas to a processor card from two different directions.
2. Background Information
Electronic components are frequently packaged in enclosures, for example to protect against contamination, electrical interference, and damage. For example, computer processor cards are conventionally packaged in an arrangement known as a processor book, in which one or more processor cards are sandwiched between two opposing covers. Referring to FIG. 1, a conventional processor book 10 is shown. The processor book 10 has covers which are connected together at their upper and lower edges using upper and lower rails 12 and 14, respectively. In this Figure, only the rear cover 16 is shown, with the front cover being removed for illustration purposes. The resulting package of rails and covers typically forms a hollow parallelepiped (i.e., a "book" shape), with the processor card 18 being located therein, and separated from the respective front and rear covers by a space. The parallelepiped is open along one edge, so that the processor card 18 can be connected to a backplane 20.
The processor book 10 is arranged within a computer housing (not shown) so as to be perpendicular to the backplane 20. Further, the processor book 10 is positioned between an upper and a lower cage shelf located within the computer housing. For illustration purposes, only the lower cage shelf 24 is shown. The lower cage shelf 24 includes guides 26 which engage with lower rail 14, and ensure that the processor book 10 is properly located. Likewise, the upper cage shelf (not shown) is provided with similar guides for engaging with the upper rail 12.
During operation, the processor card 18, and in particular, the processor modules (not shown) attached to the processor card, tend to consume a substantial amount of electrical power, and therefore generate a substantial amount of heat. Because excess temperature can impair a computer system's reliability and functionality, the processor cards 18 are provided with heat sinks 28 in a region of the respective processor modules, to help dissipate the generated heat. In the Figure, the heat sinks 28 hide the processor modules from view.
Moreover, the computer system is typically provided with one or more fans 30 which cause a cooling flow of air to pass over the heat sinks 28, thus causing a transfer of heat away from the heat sinks 28. Typically, fan 30 is attached beneath lower cage shelf 24 and within a blower housing 25, so as to be located beneath lower rail 14 of the processor book 10. The cooling air is thus drawn through air vents 32 provided in the upper rail 12, over the surfaces of the processor card 18, and out through air vents 34 provided in the lower rail 14. As will be appreciated, this flow of air is essentially parallel to a surface of the backplane 20 which the processor card 18 is attached to, as indicated by arrows 36.
Conventionally, the above cooling arrangement is used with processor cards 18 in which the cards are provided with the processor modules and heat sinks 28 generally non-symmetrically located thereon, i.e., in a somewhat random pattern. However, high performance SMP (Symmetrical Multi Processor) cards have been introduced, which require an improved cooling arrangement. With SMP cards, a plurality of processor modules are located adjacent to one another and spatially arranged in series along a connector edge of the processor card, so as to be placed as close to the backplane as possible. This reduces the distance from the processor modules to the backplane to a minimum, so that the desired signal timing for running at high clock speeds can be achieved. However, since the processor modules are spatially located in series, and in a direction of the flow of the cooling air in the conventional cooling arrangement, as the cooling air flows from one processor module and associated heat sink to the next, the air increases in temperature. This substantially reduces the ability to transfer heat away from the final processor modules, i.e., those processor modules lying closest to the lower rail. As such, these final processor modules, and even others adjacent thereto, may be caused to run at high temperatures that can impair the computer system's reliability and functionality.
In order to remove the heat generated by the processor modules and keep temperatures low, it is known to attach relatively massive heat sinks to the processor modules. However, this has a disadvantageous effect, since it is desirable to reduce the size of the heat sinks as much as possible, so that a compact electrical package can be obtained. By providing for a compact electrical package, faster signal timing is possible due to shorter electrical distances for signals to travel.
It is also known to provide additional fans to increase the air flow over the processor board, or to use so-called point cooling blowers in which an additional blower is used to blow cooling air directly on a specific location of the processor board. It is also known to attach a fan directly to a heat sink to form a so-called fan sink. However, such additional fans have the disadvantage of increasing the number of moving parts, all of which are susceptible to mechanical failure. Thus, the reliability of the computer system may be disadvantageously reduced with such arrangements. Further, the added fans take up additional space, disadvantageously reducing the compactness of the system.
Therefore, a need existed for a way of cooling such processor cards which is reliable and efficient, and which does not disadvantageously increase the size of the system.